Thousands of troops have been deployed, a curfew imposed and internet services suspended, in efforts to quell the mass protests taking place in some areas of the state. There have been pitched battles between police and demonstrators. At least two people have died and seven policemen have been injured in clashes.
But the protests in Assam - the first in the country after the bill was passed - have little to do with concerns about the exclusionary nature of the bill and the threat to secularism.
They have more to do with indigenous fears about being demographically and culturally swamped by “outsiders”.
One reason for the tensions is that Assam is one of India's most complex and multi-ethnic states. Assamese and Bengali-speaking Hindus live here, as do a medley of tribespeople. A third of its 32 million residents are Muslims, the second-highest number in any part of India after Indian-administered Kashmir.
It is also one of India's most fragmented and troubled regions: four north-eastern states have been carved out of Assam and three groups of tribespeople living there want to break away and form their own states.
Residents have clashed over linguistic identity and citizenship.
- BBC.com